Research: Taking Vitamin D Supplements Appears to Lower Risk of Multiple Sclerosis
Kathi
Multiple Sclerosis
02-16-2004
ST. PAUL, MN – Women who take vitamin D supplements through
multivitamins are 40 percent less likely to develop multiple sclerosis
(MS) than women who do not take supplements, according to a study
published in the January 13 issue of Neurology, the scientific journal
of the American Academy of Neurology. Food is a source of vitamin D,
and the body makes vitamin D through exposure to sunlight. "Because
the number of cases of MS increases the farther you get from the
equator, one hypothesis has been that sunlight exposure and high
levels of vitamin D may reduce the risk of MS," said study author
Kassandra Munger, MSc, of Harvard School of Public Health in Boston,
MA. "This is the first prospective study to look at this question.
"These results need to be confirmed with additional research, but it's
exciting to think that something as simple as taking a multivitamin
could reduce your risk of developing MS."
The researchers examined data from two large studies involving women,
the 20-year Nurses' Health Study and the 10-year Nurses' Health Study
II. The women's diets and use of multivitamin supplements were
assessed as the studies began and then again every four years. Women
with MS symptoms starting before beginning the study were not included
in the results. There were 187,563 women in the study. Of those, 173
women developed MS during the course of the study.
The women were divided into groups based on vitamin D use. Those with
the highest intake of vitamin D from supplements (400 IU or more per
day) were 40 percent less likely to develop MS than those who used no
supplements.
The risk of developing MS was lower both for those high in intake of
vitamin D from supplements only and for those high in intake from both
supplements and food. However, those whose intake of vitamin D was
from food only did not have any lesser risk of developing MS. The
researchers also analyzed the data while adjusting for smoking and
latitude at birth, but the results did not change.
Since supplemental vitamin D intake was mainly from multivitamins, it
is difficult to isolate the effects of vitamin D from the potential
effects of other vitamins found in multivitamins, according to Munger.
"However, none of these vitamins was itself significantly associated
with risk of MS after adjusting for total vitamin D intake or vitamin
D from supplements," Munger said.
Earlier research also points to the role of vitamin D in MS. Studies
with mice with experimental autoimmune encephalomyelitis (EAE), an
autoimmune disease in animals that is used as a model of MS, have
shown that vitamin D supplements can prevent or favorably affect the
course of the disease. Other studies have shown that people with MS
tend to have insufficient levels of vitamin D, and that periods of low
vitamin D occur before times of high disease activity, and periods of
high vitamin D precede times of low disease activity.
Munger said that future prospective studies should measure the levels
of vitamin D in the blood prior to the onset of MS.
The study was supported by grants from the National Institutes of
Health.
The American Academy of Neurology, an association of more than 18,000
neurologists and neuroscience professionals, is dedicated to improving
patient care through education and research. A neurologist is a doctor
with specialized training in diagnosing, treating and managing
disorders of the brain and nervous system such as stroke, Alzheimer's
disease, epilepsy, Parkinson's disease, autism and multiple sclerosis.
For more information about the American Academy of Neurology, visit
its web site at www.aan.com.
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